A design procedure for the handling qualities optimization of the X-29A aircraft

A design technique for handling qualities improve-ment was developed for the X-29A aircraft. As withany new aircraft, the X-29A control law designerswere presented with a relatively high degree of uncer-tainty in their mathematical models. The presence ofuncertainties, and the high level of static instability ofthe X-29A caused the control law designers to stressstability and robustness over handling qualities. Dur-ing flight test, the mathematical models of the vehiclewere validated or corrected to match the vehicle dy-namic behavior. The updated models were then usedto fine tune the control system to provide fighter-likehandling characteristics. A design methodology wasdeveloped which works within the existing control sys-tem architecture to provide improved handling quali-ties and acceptable stability with a minimum of cost inboth implementation as well as software verificationand validation. Nomenclature e FFrKl Kz K3K4 K,, feedback error (6pc - Ytc)square root of - 1fast Fourier transformationcanard feedback gainnormal acceleration feedback gainpitch rate feedback gainpilot command gainNeal-Smith compensator gain